1. Field of the Invention
The present invention relates to a sense amplifier driving device of a semiconductor memory device. In particular, it relates to a sense amplifier driving device which sequentially drives a number of sense amplifiers to reduce the peak current caused by the sensing operation.
2. Description of the Prior Art
FIG. 1 is a block diagram of a conventional semiconductor memory device. As shown in diagram, since conventional sense amplifiers sense all data on the one word line selected by the row decoder, there is a problem that the operation speed of the sense amplifiers becomes longer and the peak current is increased by the progress of the high density memory device.
FIG. 2 is a block diagram which illustrates the activation process in accordance with a conventional dynamic random access memory. As shown in diagram, /RAS signal is applied to the word line enable signal generator 10, and an output signal WL.sub.-- en from the word line enable signal generator 10 is applied to the sense enable signal generator 20. When a sense enable signal SE from the sense enable signal generator 20 is activated, a sense amplifer activation signal generator 30 which generates signals (rto and /s: bias supply voltages of sense amplifiers) is operated to perform a sensing operation of sense amplifiers.
In general, a sense amplifier array having a large number of sense amplifiers, for example 512 sense amplifiers, is controlled by only one pair of sense amplifier activation signals, rto and /s.
As a result, there is a problem that a sensing peak current which causes noise may be generated.
In order to solve this problem, the conventional art utilizes a technique which controls the voltage levels of signals rto and /s to reduce the peak current by degrading the sensing speed.
However, such a conventional technique which reduces the peak current by degrading the sensing speed is inefficient, and also there is a limit in reducing the sensing speed and the peak current.